Please don't pollute the streams. Carry baby wipes, use them along with a good deodorant and antiperspirant, pack the wipes out of the backcountry (in a ziplock bag), and dispose of them properly in a bear-proof dumpster.

More seriously, if you are worrying about this, you aren't ready for more than a dayhike. Getting out on a real backpack means you will have to go without your daily shower. Forget about shaving anywhere during your couple of months on the AT, PCT, or JMT. Basic hand washing is pretty much the maximum hygeine (minimum of 200 feet from the streams and lakes, please - don't pollute the water sources that we all have to drink from). Don't even think about washing clothes until you get home or get to a re-supply location.

As a resident of the SFBay Area, my observations indicate that only people of a certain orientation are so fastidious about their, ummmm, bodily hygiene when spending more than a partial day on the trails. The rest of us don't really care (though we have noticed that the people in the traditional after-trek pizza stop tend to move to the far end of the establishment).

"Shave? Shave? We don' need no stinkin' razors! Just pull the hairs out one at a time!"

Well, you laugh, but I recently camped in a campground on my way to start a backpacking trip. In the morning, while using the rest room, I noticed a guy in there simply reeked of after shave.

All I could think was how lucky he'd been that this particular campground (apparently) didn't have a bear problem. If he'd been in Yosemite or someplace like it, even a travel trailer wouldn't have protected him.